Courier Client SDK

A lightweight TypeScript SDK for signing EIP-712 permit meta-transactions and sending them to a relayer backend — built for seamless gasless user experiences using WalletConnect or any EVM-compatible wallet.

✨ Features

• 🔐 Sign EIP-712 permit transaction
• 📡 Relay signed transaction onchain
• 🔁 Works with WalletConnect & other EVM-compatible wallets
• ⚡ Built with Ethers.js and TypeScript

📦 Installation

npm install courier-client-sdk
# or
yarn add courier-client-sdk

🚀 Usage

1. Sign a Permit

import { signPermitTypedData, submitSignedPermitData} from "courier-client-sdk";
import { useWalletClient } from "wagmi";


const { data: walletClient } = useWalletClient();

const result = await signPermitTypedData({
  token: "0xTokenAddress",
  owner: "0xTokenOwnerAddress",
  amount: BigInt(1000),
  deadline: BigInt(Date.now() + 3600 * 1000),
  walletClient
});

console.log(result); // { v, r, s, deadline }

2. Send to courier handler

const tx = await submitSignedPermitData({
    token: "0xTokenAddress",
    owner: "0xTokenOwnerAddress",
    recipient: "0xBeneficiaryAddresss",
    amount: BigInt(1000),
    result.deadline,
    result.v, 
    result.r, 
    result.s,
});
const {hash} = await tx.json();
console.log(hash);

📁 Project Structure

src/
  ├── signPermitTypedData.ts
  ├── sendPermitToBackend.ts
  └── erc20Permit.ts
dist/
  └── (generated on build)

💠 Development

git clone https://github.com/0x1codegod/Courier-client-sdk.git
cd Courier-client-sdk
npm install
npm run build

📄 License

MIT © 0x1codegod Twitter/X @ShedrackTheDev